This invention relates to an image processing apparatus and a method therefor and, more particularly, to an image processing apparatus and method therefor which processes an image including image regions which have to be respectively coded corresponding to different proper encoding methods.
Conventionally, in a facsimile apparatus which transmits a color image, a technique has been examined for improving the transmission efficiency and image quality by selecting an appropriate encoding method upon transmission depending on whether the image to be transmitted is a color or monochrome image. As a method of determining whether the image is a color or monochrome image, a method of manually selecting a color or monochrome image by an operator, and a method of automatically discriminating a color or monochrome image in the apparatus have been examined. In order to automatically discriminate an image in the apparatus, whether the image is a color or monochrome image is discriminated on the basis of, e.g., the ratio of R, G, and B outputs from reading sensors.
However, recently, documents have been used which include a complicated combination of a color image and monochrome binary characters in one page. Since the above-mentioned conventional facsimile apparatus discriminates whether the entire image for one page is a color or monochrome image, it is difficult to obtain an appropriate discrimination result when the image for one page includes a complicated combination of a color image and monochrome binary characters. For example, if the image includes even a small color portion, the apparatus discriminates the entire image to be a color image, and compresses the entire image by a compression encoding method such as JPEG suitable for a color image (especially, a natural image) upon transmission of the image. As a result, the following problems are posed:
The total transmission amount increases, resulting in high transmission cost. PA1 Since the compression encoding method suitable for a color image (especially, a natural image) is used, the quality of monochrome characters deteriorates.